The present invention relates to an electric motor speed controller for vehicles, and more particularly, to an electric bicycle.
Currently, makers of electric vehicles are commonly using programmable microcontroller solution for controlling the vehicle speed One of these solutions is found in U.S. Pat. No. 6,727,668 B1, the block diagram of which is shown in FIG. 1.
The controlling algorithm is pre-programmed in programmable microcontroller 144, where one of the external inputs is the user's throttle command. Multiphase motor 110 is formed by a rotor 120 and stator 130. DC source 140 drives different phases of the motor via switch sets 142, which are controlled by the controller 144 via gate drivers 146. Current conditions of different phases are feedback to controller 144 by current sensor 148, while position and speed information is feedback via position sensor 146 and speed approximator 150 respectively. According to these feedback signals, controller 144 adjusts switch sets 142 to achieve the reference, the user input.
However, due to the use of programmable microcontrollers, this solution is costly. The present invention overcomes this drawback by using simple logic gates and counters to implement the motor speed controller. It can be integrated easily into silicon and hence provide a lower cost system solution where no programmable microcontroller is required.